A known apparatus (fusion splicer) for mutually fusing and splicing optical fibers is an apparatus for gripping a coated part of the optical fiber by an optical fiber gripping part and receiving a bared optical fiber part exposed to the distal end beyond this coated part in a groove of a groove stand formed in the inside beyond the optical fiber gripping part and aligning the bared optical fiber part (for example, see Patent Reference 1).
An optical fiber holder which is the optical fiber gripping part of the fusion splicer has a holding lid rotatably joined to the back side of the fusion splicer beyond a position in which the optical fiber is gripped, and the optical fiber is gripped or its grip of the optical fiber is released by opening this holding lid from the front side to the back side or closing the holding lid from the back side to the front side. Also, the fusion splicer includes an apparatus for providing the back side beyond the optical fiber holder in the fusion splicer with a reinforcing work part for reinforcing the fused optical fibers by a heat-shrink tube etc.